Communications system supporting multiple sector sizes

Abstract

In one embodiment, a configurable communications system accommodates a plurality of different transmission word sizes. In a transmit path, the system inserts a number of padding bits corresponding to missing user-data bits onto the end of an input data sequence to generate a set of data having N bits. The N bits are interleaved and error-correction (EC) encoded to generate parity bits corresponding to an EC codeword. The parity bits are de-interleaved and multiplexed with the input data stream to generate a transmission word. In a receive path, a channel detector recovers channel values corresponding to the transmission word. Padding values, corresponding to the missing-bit locations, are inserted among the channel values. The resulting channel values are interleaved and EC decoded to recover the EC codeword. The data bits of the codeword are de-interleaved, and the padding bits corresponding to the missing channel values are discarded.

What is claimed is: 
     
       1. A computer-implemented method for generating a transmission word for a set of user-data values, the method comprising:
 (a) adding, by a padding-value inserter, a set of padding values to the set of user-data values to form a dataword; 
 (b) interleaving, by an interleaver, the dataword; 
 (c) encoding, by an encoder, the interleaved dataword to generate a codeword comprising the set of user-data values and a set of parity values; and 
 (d) generating, by a transmission-word generator, the transmission word comprising the set of user-data values and the set of parity values, wherein: 
 the transmission word is smaller than the codeword; 
 the interleaving of step (b) is local/global interleaving; and 
 step (b) comprises: 
 (b1) the interleaver interleaving on a local unit basis, a first subset of dataword values to generate a first group of two or more global units; 
 (b2) the interleaver interleaving on the local unit basis, a second subset of dataword values to generate a second group of two or more global units; and 
 (b3) the interleaver interleaving on a global unit basis, greater than the local unit basis, at least the global units of the first and second groups to generate the interleaved dataword. 
 
     
     
       2. The method of  claim 1 , wherein the transmission word does not include any of the padding values. 
     
     
       3. The method of  claim 1 , wherein the method further comprises, prior to step (a):
 (i) receiving a programmable value corresponding to size of the transmission word; and 
 (ii) selecting, based on the programmable value, (1) size of the set of user-data values and (2) size of the set of padding values. 
 
     
     
       4. The method of  claim 1 , wherein the method further comprises interleaving the set of user-data values prior to step (a). 
     
     
       5. The method of  claim 1 , wherein step (d) comprises:
 (d1) de-interleaving the parity values to generate de-interleaved parity values; and 
 (d2) multiplexing the de-interleaved parity values and the user-data values to generate the transmission word. 
 
     
     
       6. The method of  claim 1 , wherein, in step (a), the padding values are appended at the end of the set of user-data values to form the dataword. 
     
     
       7. An apparatus for generating a transmission word for a set of user-data values, the apparatus comprising:
 a padding-value inserter configured to add a set of padding values to the set of user-data values to form a dataword; 
 an interleaver configured to interleave the dataword; 
 an encoder configured to encode the interleaved dataword to generate a codeword comprising the set of user-data values and a set of parity values; and 
 a transmission-word generator configured to generate the transmission word comprising the set of user-data values and the set of parity values, wherein:
 the transmission word is smaller than the codeword; 
 the interleaver is a local/global interleaver comprising:
 a local interleaver configured to:
 interleave on a local unit basis, a first subset of dataword values to generate a first group of two or more global units; and 
 interleave on the local unit basis, a second subset of dataword values to generate a second group of two or more global units; and 
 
 a global interleaver configured to interleave on a global unit basis, greater than the local unit basis, at least the global units of the first and second groups to generate the interleaved dataword. 
 
 
 
     
     
       8. The apparatus of  claim 7 , wherein the transmission word does not include any of the padding values. 
     
     
       9. The apparatus of  claim 7 , further comprising a controller configured to:
 receive a programmable value corresponding to size of the transmission word; and 
 select, based on the programmable value, (1) size of the set of user-data values and (2) size of the set of padding values. 
 
     
     
       10. The apparatus of  claim 7 , further comprising partitioning circuitry configured to interleave the set of user-data values prior to the padding-value inserter adding the padding values to the set of user-data values. 
     
     
       11. The apparatus of  claim 7 , wherein the transmission word generator comprises:
 a de-interleaver configured to de-interleave the parity values to generate de-interleaved parity values; and 
 a multiplexer configured to multiplex the de-interleaved parity values and the user-data values to generate the transmission word. 
 
     
     
       12. The apparatus of  claim 7 , wherein the padding-value inserter is configured to append the padding values at the end of the set of user-data values to form the dataword. 
     
     
       13. The apparatus of  claim 7 , wherein the apparatus is an integrated circuit.